Wide jet soot blower

ABSTRACT

A method of cleaning a cooling pipe wall in fire and radiation chambers of boilers by means of a steam-operated wide jet soot blower having rearwardly directed blow nozzle means. A blowpipe is adapted to be advanced away from and retracted into the cooling pipe wall linearly during rotation simultaneously occurring to direct the nozzle means along a rotating path. There are steps of moving the blower with the nozzle means thereof closed in a direction linearly away from the pipe wall to a location representing approximately the intended maximum distance of the blower from the pipe wall to be cleaned, opening the nozzle means only when the blower has reached the location, and subsequently moving the blower with the nozzle means open along linear distance during rotating that results in directing the nozzle means in a rotating path back toward and into said wall while closing the nozzle means when the blower during its simultaneous linear and rotating movement back toward the wall has reached a desired safety distance from the wall.

United States Patent Gummersbach (Rhineland), Germany [54] WIDE JET SOOTBLOWER 2 Claims, 3 Drawing Figs.

[52] US. Cl l22l30 [51] lnt.Cl F22b 37/48 [50] Field ofSeai-ch .4122/390,

[56] References Cited UNITED STATES PATENTS 2,722,033 ll/l955 Glinn etal. 122/392 2,737,681 3/1956 Elmendorfm, 15/318 3,344,459 10/1967Jankowski 15/317 l I w Primary Examiner Kenneth W. SpragueAttorney-Walter Becker AMSTRACT: A method of cleaning a cooling pipewall in tire and radiation chambers of boilers by means of asteamoperated wide jet soot blower having rearwardly directed blownozzle means. A blowpipe is adapted to be advanced away from andretracted into the cooling pipe wall linearly during rotationsimultaneously occurring to direct the nozzle means along a rotatingpath. There are steps of moving the blower with the nozzle means thereofclosed in a direction linearly away from the pipe wall to a locationrepresenting approximately the intended maximum distance of the blowerfrom the pipe wall to be cleaned, opening the nozzle means only when theblower has reached the location, and subsequently moving the blower withthe nozzle means open along linear distance during rotating that resultsin directing the nozzle means in a rotating path back toward and intosaid wall while closing the nozzle means when the blower during itssimultaneous linear and rotating movement back toward the wall hasreached a desired safety distance from the wall.

WIDE JET SOOT BLOWER The present invention relates to a wide jet sootblower and a method of operating the same. The invention concerns inparticular push or wide jet soot blowers which are employed for keepingclean the walls of cooling pipes in fire and jet chambers of boilerspreferably heated by coal and which are arranged axially displaceableand rotatable in a protective pipe which extends through the outerboiler wall covered by cool ing pipes, with the axis of said protectivepipe substantially perpendicular to said outer wall surface.

With wide jet blowers of this type, the blowing head equipped withrearwardly directed steam blowing nozzles is in rest conditionrelatively cool and is located within said protective pipe. According toone embodiment of such soot blowers, the soot blower is for purposesofcleaning blowing moved out of said wall while simultaneously rotatingabout its longitudinal axis into the fire or jet chamber to a certainmaximum end position and subsequently is returned into said protectivepipe. The nozzles arranged in said blowing head will, during thisblowing operation, carry out a rotating movement.

With this embodiment, the blowing valve was expediently openedsimultaneously with the moving outwardly of the blowing head into thefire chamber while, however, always a a a certain safety minimum spacewas maintained between the blowing head or the blowing nozzles thereofand the surface of the cooling pile wall to be cleaned.

In spite of this safety measure, frequently already during the firstmonth of operation outer tears and damage were observed on those boilerpipes which were located in the immediate vicinity of the soot blower.Such tears and other damage could not be completely avoided even byincreasing the said safety distance.

Further investigations have shown that these pipe damages were causednot by the hot steam employed for the blowing operation but are due tothe condensate which collected during the rest position and inparticular during the warming of the blower and the steam pipes leadingthereto.

It is, therefore, an object of the present invention to provide a widejet soot blower which will overcome the above-mentioned drawbacks.

It is another object of this invention to provide a method of operatinga wide jet soot blower which will result in avoiding the above-outlineddrawbacks heretofore encountered with wide jet soot blowers.

These and other objects and advantages of the invention will appear moreclearly from the following specification in connection with theaccompanying drawing, in which:

FIG. I is a cross section through the wall of a wide jet soot blower ina plane which contains the blower axis;

FIG. 2 diagrammatically illustrates the pertaining lateral view of thewall surface;

FIG. 3 shows a soot blower which is particularly well suitable for usein connection with the present invention.

The invention is based on the observation that when opening the blowingvalve, the immediately pushed out condensate first enters the firechamber in the form of a rather compacted jet and then after a certaindistance from the blower dissolves itself into a cloud of fine waterdroplets which no longer do damage to the pipes hit thereby.

With heretofore-known wide jet blowers which are provided with a blowinghead rotating in the same sense of rotation and at constant angularspeed and the steam nozzles of which are blowing in rearward directiononto the cooling pipes which are to be cleaned and pertain to therespective fire chamber wall, the length of the blowing jet decreasesfrom the start of the blowing with increasing path of the blowing headuntil the blowing head has reached its outermost end position in thefirechamber approximately corresponding to the radius of an Archimedesspiral. The length of the blowing jet is thus with fully moved out blowhead greater by a multiple than when passing the above-mentionedrelatively short safety distance.

Inasmuch as the destructive effect of the quantities of condensatecontained in the steam jet considerably decreases with increasing lengthof the blowing jet, and inasmuch as due to the constant angular velocityof the blow head, the effective time or duration ofthe blow jet, withregard to the wall surface unit, decreases with increasing blowingradius, it will be evident that according to the present invention adouble safety against the erosions caused to the cooling pipes by thesteam condensate will be realized because the force as well as theduration of the condensate jet per surface unit of the cooling pipeswill be considerably reduced.

The above-outlined inventive idea can be realized in a particularlysimple manner with that type of heretofore known blowers in which theblowing pipe, for instance, by means ofa thread-shaped guidingarrangement moves forwardly and rearwardly along a rotating path and ispreferably rotated by a gear driven from the outside while said blowingpipe is axially displaceable relative to said gear, and in which saidblow pipe is first moved along a rotating path forwardly into the firechamber while, when exceeding the safety distance, the blow valve isopened, whereupon when, during its further outward movement the blowhead reaches its end position in the fire chamber, the direction ofrotation of the blow head relative to the stationary housing is reversedwhereby the return movement is initiated. Simultaneously, the blow valvecloses and the blow head returns to its end position into the protectivepipe in the wall. With this design, the rotating movement of the blowpipe may, of course, also be effected by other means, for instance, bymounting the same between inclined rollers.

Inasmuch as the automatic control of the individual operations of theentire working cycle is effected by the cooperation of a control discconnected to the end of the blowing pipe and having an annular shape, ifdesired, provided with a flange with a control rail which is tiltablyjournaled in a housing and axis parallel to the blowing pipe, it will bepossible for the average expert in the field familiar with the blowerconstrue tion also expediently to adjust or change the actuation of thecontrol disc and control rail when reversing the originally providedturning direction. The control rail acts upon the blowing valve and theelectric control switches for the motor drive of the blowing pipe.

The operation of the blower will now be described in con nection withthe movement of the blowing head and the range of actuation of theblowing jet. Specifically referring to the drawing, the fire wall iscovered by cooling pipes R which are arranged closely adjacent to eachother and are passed through by the boiler working medium. A protectivepipe R, extends through said wall of cooling pipes in a directionsubstantially perpendicular to the wall surface formed by said coolingpipes. Within the protective pipe R, there is guided the blowing pipe ofthe blower, which blowing pipe has its outer end provided with theblowing head K whereas the blowing pipe when in rest position isprotectively arranged within said protective pipe R,

That plane which is parallel to the wall of cooling pipes and is tangentto the cooling pipes R while being located on the side of the firechamber is designated with the reference character W. It is from thissurface W that the decisive axial distance of the blowing head or steamnozzles thereof is measured for the blower when the latter is inoperative position. In particular, the minimum or safety distance a, isimportant because it must not decrease during the operation, i.e. whilesteam leaves the nozzles. The maximum distance of the blower reached inthe end position of the latter is designated as a,,,,,,, and shown inFIG. 1.

The true length of the blow jet is, of course, in conformity with themagnitude of the angle of inclination of the blow nozzle with regard tothe blowpipe axis considerably greater, however, always proportional tothe respective axial distance a of the blow head from the plane of thewall. The true length of the blow jet corresponds to the straight linesleading from the points 0. l, 2 and 3 of the wall surface to thecorresponding centers of the blow head.

FIG. 2 shows the Archimedes spiral 1 -2 3 which is described by the blowjet (reduced to its center line) on the wallsurface during the actualblowing. in conformity with the invention, the blow head (when the blowvalve is closed) will first in a direction opposite to the directionindicated by the arrows move along a rotating path simultaneously withlinear movement out of the wall formed by the cooling pipe R and whenreaching its outermost end position with the axial distance a,,,,,, willopen the blow valve and at the same time will reverse its sense ofrotation so as to move in the direction indicated by the arrows. Thecondensate shock occurring each time when starting the cold blower willthus move over the longest possible blowing path before impacting uponthe cooling pipes.

Subsequently, the blowing pipe (in conformity with the illustratedexample with three complete revolutions) moves, while blowing, back topoint 3 into the wall; then, when passing point 3 or the axial distancea,, the blow valve is closed and when reaching the innermost (notillustrated) end position, the blowpipe comes to a rest at which timealso the blow head is located completely within the protective pipe R,and is shrouded against any heat radiation from the fire chamber.

FIG. 3 shows a soot blower type for realizing the present in vention.More specifically, the soot blower of FIG. 3 comprises a blowpipe Bprovided over a limited length with an outer thread Ga. The free innerend of said blowpipe B carries the blow head K and when turned in onedirection moves into the fire room while when being turned in theopposite direction it moves out of the fireroom.

Blowpipe B is concentrically surrounded by a gear Z having an innerbushing C and being adapted to be rotated in either direction by areversible electric motor M through the inter vention of a pinion D.

That longitudinal portion of blowpipe B which is provided with an outerthread Ga is guided in a threaded sleeve Gi (inner thread) of thestationary blower frame, whereas the outwardly adjacent blowpipe portionis up to control discs S provided with tongues extending in axialdirection and engaging the axial grooves of bushing C.

The entire blowpipe is in a rest position within a protective pipe R,which extends through the boiler wall. At the outer end of the movableblowpipe there is fixedly arranged a circu lar control disc S which whenthe blow head freely extends into the fire chamber, with itscircumference moves in a sliding manner below a control rail L over theentire length thereof and, in view of its turning movement (in onedirection only of the two directions of rotation) pivots laterally aboutan axis parallel to the blow pipe whereby by means ofa linkage the blowvalve V of the blower is opened and during the contact between controldisc and control rail L is kept open.

This arrangement thus brings about that the blower valve will be openonly as long as the blow head passes through a certain area in the firechamber in a certain direction of rotation.

It is, of course, to be understood that the present invention is, by nomeans, limited to the particular showing in the drawing but alsocomprises modifications within the scope of the appended claims.

What we claim is:

1. A method of cleaning a cooling pipe wall in fire and radiationchambers of boilers by means of a steam-operated wide jet soot blowerhaving a rearwardly directed blow nozzle means and being equipped with ablowpipe adapted to be advanced linearly away from and retracted intosaid cooling pipe wall while nozzle means move along a rotating path,which includes the steps of moving said blower with the nozzle meansthereof closed away from said pipe wall to a location representingapproximately the intended maximum distance of said blower from the pipewall to be cleaned, opening said nozzle means when said blower hasreached said location, and subsequently moving said blower with saidnozzle means open along a path back toward and into said wall linearlywhile closing said nozzle means durin rotation when said blower duringits movement linearly bac toward said wall has reached a desired safetydistance from said wall so that pipe damage otherwise caused by initialhot steam condensate is avoided.

2. An apparatus for cleaning a cooling pipe wall in fire and radiationchambers of boilers, which includes: a wide jet soot blower comprising ablow pipe with a blow head having blow nozzle means adapted and closed,driving means operatively connected to said blow pipe and operable tomove said blow pipe linearly while said nozzle means move along arotating path in the rotation direction with said nozzle means in closedcondition, and control means operatively connected to said blow head andsaid nozzle means and operable in response to said blowpipe havingreached a desired maximum distance from the pipe wall to be cleaned toreverse the movement of said blow pipe while causing said nozzle meansto open and subsequently to close in response to said blowpipe reachinga desired minimum distance from the pipe wall to be cleaned so that pipedamage otherwise caused by initial hot steam condensate is avoided.

1. A method of cleaning a cooling pipe wall in fire and radiationchambers of boilers by means of a steam-operated wide jet soot blowerhaving a rearwardly directed blow nozzle means and being equipped with ablowpipe adapted to be advanced linearly away from and retracted intosaid cooling pipe wall while nozzle means move along a rotating path,which includes the steps of moving said blower with the nozzle meansthereof closed away from said pipe wall to a location representingapproximately the intended maximum distance of said blower from the pipewall to be cleaned, opening said nozzle means when said blower hasreached said location, and subsequently moving said blower with saidnozzle means open along a path back toward and into said wall linearlywhile closing said nozzle means during rotation when said blower duringits movement linearly back toward said wall has reached a desired safetydistance from said wall so that pipe damage otherwise caused by initialhot steam condensate is avoided.
 2. An apparatus for cleaning a coolingpipe wall in fire and radiation chambers of boilers, which includes: awide jet soot blower comprising a blow pipe with a blow head having blownozzle means adapted and closed, driving means operatively connected tosaid blow pipe and operable to move said blow pipe linearly while saidnozzle means move along a rotating path in the rotation direction withsaid nozzle means in closed condition, and control means operativelyconnected to said blow head and said nozzle means and operable inresponse to said blowpipe having reached a desired maximum distance fromthe pipe wall to be cleaned to reverse the movement of said blow pipewhile causing said nozzle means to open and subsequently to close inresponse to said blowpipe reaching a desired minimum distance from thepipe wall to be cleaned so that pipe damage otherwise caused by initialhot steam condensate is avoided.